Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Hey you welcome to Stuff to Blow your Mind. My name is Robert Lamb, and I am Joe McCormick, and we're back with another Invention themed episode. Some of you may notice Joe and I were just chatting about this. We were doing an episode here on ice skating. It is, of course the very beginning of summer.
Most of the articles you find about this come out in December, so actually you might be much more familiar with the seasonal mismatch if you live in the Southern Hemisphere. But yeah, I guess for the majority of readers in the Northern hemisphere reading, I guess they're only going to click on an article about ice skating in December. I don't know. I'm against that kind of thing. I believe in anti seasonal topicality.
Yeah, I mean, plus, people are ice skating somewhere year around. There are of course indoor ice skating rinks. And I should also mention that the way we're getting to ice skating is because my initial inspiration here was to do an episode on roller skating. This is of course, the past time that initially boomed during the so called Golden Age of roller skating, This is roughly nineteen thirty seven
through nineteen fifty nine. I think there's a lot of you know, escaping from the darkness of the world in that period and finding a little lightheartedness on the roller skates in the skating rink. But you know, it's something that's never completely gone out of fashion either, and it's experienced sustained popularity in various parts of the world and saw a major boost during the global pandemic.
Can I ask a question to older listeners if you watch movies about the fifties, you often see people roller skating down the hallway in high school or in another setting that's not a dedicated roller skating environment like a rink or something, and people just roller skating on the sidewalk at school going from class to class. Is that a thing people?
Actually, I don't know they're doing it now because roller skating is not only going strong, but it's I think it's getting stronger. We may get into this in a in another episode, but there are a lot of like financial I saw some financial papers talking about how the roller skating industry is just going to continue to grow over the next decade or.
So I do think we should bring back the roller skate mounted server at the drive in restaurants, because that's interesting. It adds an element of danger and theatrical athleticism to the dining out experience that you don't usually get.
Well, I don't know how dangerous it is, but yes it is. There is kind of a neat charm to it. But yeah, I've been seeing a lot of roller skaters recently. My kid is involved in a local vibrant skating club, and it really made me reconsider what I thought I knew about skating and skating culture. So I figured, hey, well let's let's do a nice summer episode about roller skating. But the thing is, before you can even begin to cover the invention of roller skates, you have to explore
their cold weather predecessor. You have to talk about ice skates.
I assume there's no disputing this at all, which came first. The ice skate is definitely older than the roller.
Skate, definitely, definitely by a considerable margin. Yeah, nobody's even making the case, even if you were getting into potential possible examples of somebody designing something like a roller skate that just wasn't usable. Anywhere, because maybe you lacked the places for I've I've seen no arguments that this is the case. If anyone out there is aware of even any just unhinged theories about the roller skate coming before the ice skate, send it our way and we will evaluate.
But as far as I can tell, nobody's making this case, and so we're going to stick to what seems to be the established lower here. We're going to talk about ice skating now, and then I think maybe an episode later in June, we'll come back and discuss roller skating in more detail. Fair enough, Okay, So, as is generally the case when we're talking about an invention, we like to talk about what comes before, so we can appreciate the invention. What came before skating on the ice using
some sort of an ice skate. Well to properly consider ice skates. Oh wait, you already have an answer. Let's have it.
No, I was going to slipping on the ice, slipping and falling game first.
Well, it always does in ice skating, doesn't it. You could and you could make an argument that skating on the ice one way or another is slipping in style. It is a controlled slip.
Exactly controlled slipping.
Yeah, I think the most important thing that I quickly realized looking at the history of the ice skate is we think of ice skating more as novelty, or perhaps you think of it as part of sport, but we really have to view ice skates not as an item of recreation, but as a mean of conveyance, of moving the human body from one point to another. And so before humans skated across ice as a means of conserving energy and maximizing speed, they did a few different varied
things on ice, including slipping and falling down. Of course, walking across the ice is of course the oldest forerunner, obviously requiring no technology, but certainly benefiting from a variety of innovations that would occur over human history, including the leather shoe I believe, the oldest surviving example being a some five five hundred year old arny one shoe from
Armenia or what is now Armenia. But obviously such footwear was biodegradable by its very nature, so who knows what we lost though?
Of course, when we think about ice skates, these are obviously tools designed to decrease friction on the ice and allow you to glide more easily. I would tend to think that the earliest ice traversal technologies were exactly the opposite. They would be things disa to help you better grip the ice to avoid slipping and falling while you walked.
Yeah, which brings our mind to things like spiked cleats. I was looking around. Let's say there's some examples that survive from the first and second millennium CE, But again there's no telling what was lost as well in our ability to figure out how to make grippier footwear for walking around on the ice. And then, on top of this, we should also point out that a certain understanding of the different types of ice and how it responds to your weight would also have been important for moving across
the ice. The examples of the oldest surviving cleats that I was finding my research were things from the Viking era, So it's very possible there are older examples of this that didn't survive, and possibly something that didn't come up with my research. So as always, if anyone knows of an earlier example of some sort of grippy footwear technology, send it our way. Furthermore, before humans turn to ice skating, proper they make use of sleds, a variation of the sledge,
which itself is a predecessor to the cart. And these of course are ancient and widespread innovations which, depending on the environment and you know where they were constructed, they might have entailed bone, ivory or wood. So we can easily imagine that the idea for the ice skate perhaps comes together from ruminations on existing sled technology, you know, like what if ice strapped a sled to my foot, as well as experiences walking, sliding, slipping on ice covered lakes, rivers,
and so forth. Couple that with a need for such skates for a conveyance, such as areas where human communities are separated by expansive frozen over bodies of water. And it's only a matter of time till someone tries to miniaturize the whole affair and place it on a boot. Those will discuss the physicality and indeed physics of ice skating differs significantly from either of these pre existing technologies.
So here in a bit we're going to go back and look at the most ancient known examples of ice skates, how they worked and didn't work, and how they evolved. But let's go ahead and move towards our current understanding of the ice skate and just talk about how it works.
As in, what physics principles does the ice skate take advantage of?
Yeah, because we can all sort of have innate understanding of out works. But yeah, let's get into the physics. Yeah.
So this is one of those things that seems like a question that would have a fairly simple, well understood, well agreed upon answer, But surprisingly, no, the physics of ice skating are quite complicated. The issue is still being investigated.
Some explanations that you see all over the place and appearing, I think even in fairly recent physics textbooks are actually disputed by experts, and from what I can see, new papers on the physics of ice skating still appear regularly in scientific journals, at least as of a couple of years ago.
That's crazy. It's not settled science yet.
Yeah, there is a lot we do know now, but a lot of that was established rather recently, and then there are still a bunch of questions that we don't have answers to yet. But I always think it's interesting when you come across something like this, one of those things that you assume would have a short, simple, non controversial, one paragraph answer in the physics textbook, and actually it's
like a super complicated unsolved question. But anyway, so the main thing that we need to explain when looking at the physics of ice skating is why can an ice skater glide with such low friction? That's the main physics question. To illustrate this, you can quite well imagine the scenario. You don't really need to do the experiment. We know well enough from walking on various services how this would work.
Imagine you put on a pair of ice skates, you stand on a flat stretch of parking lot, and you get somebody to stand behind you and give you a push. Is that gonna work? Are you going to glide? No, that's all right. The blades will not glide smoothly over the surface of the pavement the way they would over the ice. They will know, I wrote here on my notes that they will I was gonna say, grind to a stop, but they probably won't even grind to a stop.
They're just not going to move at all. They will be clamped to the ground where you are standing, and any forward momentum you had from the push somebody gave you will cause you to fall in your face because the blades are not going to go anywhere. They will grip the ground and the top half of your body will go forward. The friction defeats the momentum, so the friction is the problem. The physical principles that make low
friction skating possible on ice are still under investigation. That said, the best and most up to date core research that I could find on this was summarized in a December twenty nineteen there's December again. December twenty nineteen review article in the journal Nature by Daniel Bond called the Physics of Ice Skating and a bit of background on the author here. Daniel Bond is a physicist affiliated with the
Institute of Physics at the University of Amsterdam. Bond specializes in fluid mechanics, among other things, so you'll see him writing articles on these kinds of topics, sometimes aimed at a more popular audience. But a couple of notable achievements that I wanted to mention of his because they're kind of indirectly connected to this topic. This will take us a little bit of field, but I think it's an
interesting parallel. Bond was involved in research you might remember from roughly a decade ago, building on some earlier research about how the massive stone blocks that were used to build the pyramids were probably transported across the ground to the building site. Of course, this was a serious question because each stone piece is enormous. The amount of force required to move it across the ground, it's hard to imagine you would have had tons and tons of workers pulling.
They were probably mounted on these sledges and moved along with great difficulty. But Bond and colleagues discovered that you could greatly decrease the friction between the sandy ground and a sledge used to transport a stone block by slightly wetting the sand in front of the sledge. They found that you want to add something like two to five percent water per unit of sand by volume, and this can reduce roughly by half the amount of force and thus the number of workers needed to pull the stone
along the ground. Now why would the water do that? Essentially, the water here helps the sand grains stick together rather than flow, so the sand functions more like a solid, flat surface when you wet it this way dry sand when you're pushing something really heavy through it, it tends to get kind of pushed out in front of the load, forming this mound that then takes more force to pull past.
You can kind of imagine this. It's like as you're dragging, you're constantly like building a little mountain in front of where you're trying to go.
Yeah, yeah, that makes sense.
But when you wet the sand, it doesn't do that as much. It forms more of a solid flat surface and you can drag it over the top more easily. Bond compared the benefits of wet sand here to the reason that you want to use wet sand to build a sand castle. It sticks together and holds its shape better. Another cool at side about that discovery about the wet sand is that this process of pouring out water on the sand in front of a stone work during transport
was actually depicted in ancient Egyptian art. So this is not really even a hypothetical process. It was instead investigating the physics principles of a process that ancient Egyptians depicted themselves doing. So there's like one example here is there's a tomb from the Middle Kingdom twelfth dynasty about nineteen
hundred BCE. Belonging to a governor called Jehudi Hotap. That shows teams of workers sporting this big statue and they're pulling it with ropes as it's mounted on a sledge, and then it shows workers pouring water out of jars
on the ground right in front of the load. This was previously interpreted as a libation, like a ceremonial pouring out of liquid as an offering to the gods, but this discovery completely reframes that pouring out of liquid as something that was very likely functional in nature, whether or not it had ritual significance, which it might also have had.
Yeah, you can very well imagine it having both, and yeah, then it makes the ritual even more potent by knowing that you can see the results right away.
Yes, so Bond was involved in that research. But one more funny thing about him. He was part of the team that won the twenty twenty four Igno Bell Prize for chemistry. We didn't talk about the chemistry prize in our in our last episodes.
Did we?
But this was quote for using chromatography to separate drunk and sober worms. I feel kind of sad we didn't cover this anyway. I looked it up to figure out what this was about. The issue is it was not really about worms. Instead, the worms were being used as a model to test different methods, different methods of sorting
different kinds of polymers. So the sober worms represented what are called active polymers that can move around, and the drunk worms were non active polymers because they just kind of chill anyway. All that was an aside on Bond's previous work. Here Bond is writing an article reviewing recent
ice skating research. It's a short review in the journal Nature, summarizing both the previous state of research on ice skating, as well as especially a new paper published in the journal Physical Review X by Canali at All from that
same year, from twenty nineteen. So Bond begins by talking about the explanation that has long been given sort of the older textbook explanation for why ice skating works, and that is that at the interface between the blade and the surface of the ice, there is a thin layer not of ice, but of liquid water, and this thin layer of water lubricates the contact between the two solid objects, between the blade and the ice. Now, why would that happen,
Why would that liquid water be there. There are several different explanations that have been offered throughout the years. One is the idea of surface melting. This is the concept that there's sort of a quasi liquid layer of water that exists on the surface of ice, generally primarily at higher temperatures, though still below freezing, and this is sometimes called pre melt. Another idea, this is commonly sighted but now disputed by Bond and by many others. And I'll
get to the reason why in a second. But this idea is pressure melting at the contact point. So under this hypothesis, like the weight of a human body distributed over the small surface area of the bottom edge of a skate blade creates so much pressure at that contact point that it causes the ice crystals to melt and become water. And thus you get your lubricating layer of water. And then the final possible explanation for that layer is
frictional heating. So we know what frictional heating is. When you rub things together, the friction generates heat. This idea here says that this kind of frictional heating happens between the skate and the ice. The heat melts the ice and the thin layer of slippery melt water is formed.
I've come across sources, especially older ones, that favor the explanation based on pressure melt melting, but Bond says this is now widely thought to be incorrect because apparently this would not work at temperatures below negative twenty degrees celsius. And we can see that ice skating regularly works well at temperatures lower than that, So just the observation of
ice skating does not match that explanation. So then maybe is it surface melting that pre melt the quasi liquid layer on the outside, or is it frictional melting leading
to a liquid layer on top of the ice. Strangely, Bond says, neither of those seem to fully explain what's going on either, especially not in the idea that they could just create a layer of liquid water, because, for one thing, these mechanisms would be equally present at the surface of other various solids that you cannot skate on. So there must be something else at place, something special
about water ice compared to other solids. Another interesting question, what exactly are the mechanical properties of this lubricating layer of water. Bond points out some things that are not really consistent with the idea that water lubricates the interface between the skate and the solid surface. For one thing, you can't skate on a flat, solid surface covered in water. You think about this like imagine a flat basketball cort
or something. You drench the floor with a thin layer of water, put on some ice skates and try to skate on it. That does not work.
Yeah, yeah. Your only hope is if the heat the floor that is being covered by the water is ice. Yeah.
Yeah, so there's something special about ice. It's not enough to just have liquid water underneath your skate blade. Another interesting thing he mentions water is generally not a great lubricant, in part because it is too thin. When it gets pressed between two solids, water is easily squeezed out of the space between them like a grippier. Stickier fluid like oil or grease, makes a better lubricant because it clings to the space between the solids and doesn't get pressed
out as easily. So curious questions confounding observations here.
So you would see oil skating would be more likely to take off than this water skating.
I mean, I would imagine if you coat a floor with oil. You can probably do some good slipping and sliding on it. I don't know exactly what the skate blade but maybe but anyway, so whatever the mechanism, the idea has long been that ice skating is possible because instead of skating on solid ice crystals, you are actually gliding over a microscopic, invisible layer of liquid. What Kanali and co authors found in their paper is that this
is half true. When you skate over the ice, there is a lubricating layer of something, but it's not simply liquid water. It's actually a unique water based substance that has some properties of liquid water and some properties of solid ice. So to show this, the authors of this paper, Canali and co authors created an experiment where they were able to measure the coefficient of friction of both the ice and the lubricating layer on top of the ice at the same time. And they did this with a
device that Bond compares to a tuning fork. Here I'm going to quote from Bond's description of their experiment. Quote. The fork was made to vibrate so that a millimeter scale glass bead attached to one of its prongs oscillated across an ice surface. The bead thus functioned as a tiny ice skate, gliding for distances of the order of
tens of micrometers across the same region of ice. An accelerometer attached to the same prong of the fork as the bead measured the amplitude of the bead's oscillations parallel to the surface and compared them with the amplitude of the driving force. Canali at all use the difference in amplitude to calculate the friction force between the bead and the ice, So they did that, and then at the same time also they were measuring the oscillation of the
bead perpendicular to the ice surface. Essentially that would be sort of how it was bouncing up and down to learn things about the lubricating layer underneath the bead. And then by comparing these two different measurements based on the parallel oscillations and the perpendicular oscillations, the authors could figure out the friction coefficient between the bead and the ice and could figure out flow properties of the lubricating layer
in between them. And what they found was weird and interesting. The lubricating layer has some viscous properties, so like a thicker, stickier fluid compared to regular water, and it also had elastic behavior, meaning it can have its shape squeezed or stretched and then bounce back to its original shape like a rubber ball. It behaved neither like water nor like ice, but like a hybrid of the two.
Quote.
The author suggests that repeated sliding over the same spot generates a mixture of ice and water, which displays both elastic behavior from the ice and viscous behavior from the water. In response to a load. The resulting layer of material would be more difficult to squeeze out of gaps than ordinary water. This could, at least in part explain the layer's excellent lubrication properties. So it has something to do with the special characteristics of the outer layers of water. Ice.
In particular, other melting solids would not necessarily behave this way, and as we observe, many other melting solids do not behave this way. There's something special about H two zero bond rights quote. Few materials can form a viscoelastic liquid solid third body in response to friction and wear. That's something that makes water special. Also, Bond mentions at the end of this review that there are plenty of questions
about the physics of ice skating that remain. The lots of things we still don't know, For example, like why does the ideal temperature for reduced friction on the ice seem to be like negative seven degrees celsius. That that's a finding, but we don't know why that temperature. And another thing he points out which I hadn't quite considered, but I think is worth the certainly worth understanding. Having
a complete science of lubrication is not just trivia. This is not just like, you know, somebody goes ice skating and wonder how does this work. It's not just to satisfy our curiosity. Understanding lubrication is hugely important to human economics and technology. Bond Site's an estimate that something like twenty percent of the world's total energy consumption is lost to friction, meaning it's turned into heat and wear on components from things rubbing together. Generally that that is not
useful to us as a type of energy. Thus, better lubrication technologies could represent big improvements in energy efficiency and in the performance and durability of our machines.
Yeah, that's a great point, I thought so too.
So let no one, Let no one snicker at the idea of lubrication science is it is serious business. But anyway to bring it back around, I would summarize what I've read on this subject by saying that it seems ice skating works because the surface of regular ice, regular hexagonal crystal and ice can and usually does, become coated in a quasi liquid layer of H two oz made of some interesting mixture of liquid melt and tiny ice crystals.
And this quasi liquid layer does not act like regular liquid water, but instead has a sticky bouncy quality or what are called in the paper visco elastic qualities, and
these qualities make it an amazing lubricant between solids. This lubricating layer is not primarily created by pressure from the skater's body weight as physics as people used to say, especially a long time ago, though pressure could play some small role, it seems frictional heating between the blade and the ice probably does play some role, maybe a major one, though some of this quasi liquid layer is already naturally there on the ice within the normal temperature range for
ice skating, and then beyond that, of course, you have to think about the physical characteristics of the blades themselves. The smooth blades of the skates allow the skater to further decrease friction, more so than say the relatively rough and grippy soles of shoes or of the bottoms of your bare feet, and the blades also allow the skater
to control movement. There's greater control because they allow you to both do a pushing motion when applied to the ice one way, and a gliding motion when applied in a different way.
Which of course is the great that's part of the great fun of ice skating, this gliding sensation, the pumping your legs side to side. I don't get out and ice skate all that often. Generally, like once a year, I'll go ice skating. Oh and it's cold enough here in Atlanta, and they have some outdoor ice skating rinks. But generally I spend at least half the time i'm there relearning how to ice skate and getting my balance, and then it gets pretty fun. You know.
I haven't done it since I was a kid. There was an ice skating rink in town when I was a kid, and we would go a number of times. It's one of those things where I think I only ever did it enough to just get to the edge of not being terrible at it, and then never proceeded to go into like being able to do it.
Yeah. Yeah, I mean, like I say, I always have to relearn. At least half the time, I'm just getting my balance right and figuring out how I'm supposed to do this, allowing my confidence to build up enough, and then I'm finally in a place where I can dodge all the children out there on the rink and make a few laps that feel pretty satisfied.
This is a tangent, but this makes me think I don't know if there's a name for this phenomenon, but I would be interested in doing something on the show about these kinds of endeavors where you get stuck in the perpetual beginner zone, where you're always just like retreading or reviewing the beginner material and you never break out into actual competence of it.
Yeah, there are probably a lot of things like that, though, of course, one of the great things about hobbies is you don't actually have to be good or even competent at them. They are your hobbies, after all. But yeah, I think there are a lot of things like this where we can look to our own experiences and say, well, I almost did that, I almost served once.
Well, I feel like there are some hobbies that are more fun to spend time in the beginner zone in than others. Like with ice skating, you know, you can imagine that you'd be having more fun once you were able to feel some amount of mastery over it, whereas other things you can just be messing around in the you know, total beginner zone and it's already pretty fun to be right there.
All right, well, let's get back into the history of ice skating, and again we'll stress the caveat that the earliest examples of any given technology don't always survive or have yet to be found, especially if their biodegradable materials bound up in their production. But the oldest ice skates that I think we know of date back to roughly eighteen hundred BCE in Scandinavia, where the ancient Scandinavians seemingly
invented the technology. Some three thousand years ago, I was reading a paper by Frederico Formenti and Alberto E. Minetti. Formenti in particular has written numerous papers dealing with recreating old examples of ice skates and comparing them to other models. This particular two thousand and seven paper was titled human locomotion on ice and it was published in the Journal of Experimental Biology, and he mentioned that there's also a case to be made for Bronze Age invention of skates
in what is now Northern Russia. And I also am going to come back around to some arguments here in a bit that also point to parts of modern day China where we have some evidence of ice skating, and then also some things like ice skating I'll get into, but it seems like universally, the earliest skates that we know of they were not made of metal. They were not even made of wood entirely. They were made of bone, which makes a lot of sense. Bone is a dense,
dependable construction material for human tool use. And yeah, you can look up some images of this. In particular, I would say that Science Friday has a really good article about the paper in question here that I'm referencing, and it has some nice color images of for Minty's reconstructed
ancient skates that you can look at. They're the same images in the original paper, except in this case they're in color, and so I included one here for you, Joe, of reconstruction of an ancient bone ice skate, and it's pretty simple.
It looks like a bone with two belts looped through it.
That's right. Yeah, this would be a bone from a horse or a cow. Generally the metatarsal bone strapped to a boot via leather straps that are worked through slits in the bone. Oh, I meant to mention that. Formenti also notes that the ancient Scandinavian sagas suggest that the first ice skates were made of wood, but this is something that is present in textual evidence, but there's no archaeological findings to support this currently, so as far as we can tell, it was bone all the way back.
This reminds me of our Bone Punk episodes where we were talking about those Ice age dwellings with the huts made out of mammoth bones.
Yeah.
Yeah, I believe part of the idea there was that those were in places where wood was actually in quite short supply or would have been precious for other reasons, and thus the bone was like it made sense economic sense to use mammoth bones as a building material. I don't know if there was a similar thing in here. It might just be that the bone had properties that you would prefer for skating.
I think a lot of it comes down to those properties. Yeah, So it's thought that these would have been the first variety of ice skates that humans used. And the crazy thing is these remained in use up into the eighteenth century CE, so until fairly recently folks were still known to strap some bones to their feet and hit the ice. Now, the authors here note that these ice skates lacked the edge that you find on modern metal skates, so you
couldn't just pump along on these with your legs. That kind of that sliding and gliding motion that we were just talking about being so fulfilling. You would not be doing that on these ice skates. You wouldn't be doing a lot of tricks I'm guessing either, and whirls and whirls and so forth, because your locomotion depended pretty much entirely on your upper limbs working a pair of poles to push you along. Oh interesting, Okay, So in that it has more in common I would imagine with skiing,
which we're not really getting into today. It's going to be a separate episode at some point. Now. From and his co author point out that skates such as these would have been used for accompanying animal driven sleds or sledges. They would have been used in ice fishing or fishing from positions further out on the ice, but especially among the Dutch people, the technology soon became essential for winter
transportation via frozen rivers, lakes, and eventually canals. So think of a region where you know, where you have a bunch of frozen over rivers and or canals that are ultimately connecting different human populations, or situations where you have a completely frozen lake and you have human populations at different points across from each other across said lake. It's ultimately faster and more energy efficient to use some sort of skating technology. And yeah, for Menty stresses that it
was highly efficient. This was no mere novelty. They weren't doing this. You know, maybe it was fun, but they weren't doing it because it was fun, He writes, quote from its very conception, skating on ice was a form of human powered locomotion that was simple and effective, very cheap, and thus accessible to a large part of the population, and allowed people to reach more distant destinations than they
could do by walking or running. In fact, unless more expensive means of transport such as horses or later trains were used, ice skates were probably the most convenient locomotion tool until bicycles were built. That would have been the nineteenth century, the latter probably not being very safe on slippery roads in winter.
That's interesting, Well, I would not have thought about it that way.
Yeah, so not everywhere and certainly not year round, but that there would be places where this was just highly efficient. It was just the most the most sensible way to move from point A to point B if conditions were just right. Now, while again bone skates were ultimately a long lasting technology against superior to mere wood, it would seem by the thirteenth century CE in the Netherlands, skaters returned to wood to make use of metal in their skating,
constructing wooden skates that had metal blades. Now, these were still things that you would strap to the bottom of your shoes, and I included an image of one of these for you here, Joe. It is also not very fancy. If you didn't know you were looking at an ice skate, you might not know you were looking at an ice skate. It's like a imagine a wooden skate but with a thin metal blade, and then it is strapped or tied to your shoes.
Yeah, yeah, it looks It looks like the wooden bottom of a boat, or like a boat keel with a tiny little strip of metal blades sticking out of the bottom.
Yeah. And so for Mantiene's co author point out that the wood here would have been easy to work, the metal that they use was very durable. An interesting thing here is that these skates would apparently according to their reconstructions and their tests, would have suffered from greater friction
compared to bone skates. But their big advantage was that they allowed the user to finally propel themselves with their lower limbs, so you could seemingly throw away the poles, free up your arms, and depend almost entirely on leg power. And as such, this is really when we begin to see skating as we know it today entering the world, Because if you go to any ice skating rink, and certainly if you go to a roller skating rink, you're
not going to see people pushing around on poles. I mean, maybe there's some sort of scenario where you use poles to get your feet underneath you. But I've never seen anything like that.
Right, So I imagine it's like the thinness of the blade that allows you to just use your legs because of the way that you can angle the foot to push versus gliding, and you can't really do that with the more rounded edge of a bone.
Yes, that's my understanding. So at this point, yeah, we're kind of off to the races. We're really not purely inventing something new, but we've innovated to a very interesting place in the development of the ice skate. And during the fifteenth and eighteenth century ice skates they retain their metal wood construction, but they became about thirty percent lighter.
According for Mente, Dutch skates of the time were shorter compared to modern skates and therefore more difficult to balance on compared to what we have today, but they would have proven especially useful to them during the Little Ice Age of the sixteenth through nineteenth centuries, during which the system of rivers and canals would have proven ideal skate
routes connecting different populations and different different destinations. And then during the eighteenth century, skates on the whole became longer and enabled easier balance and resulted in lower resistance the weight spread out across longer blades. And I've included another photo Formenti's work here reconstruction. This is still something you strapped your existing footwear, but it is even more identifiable, I think as an ice skate.
Oh yeah, totally.
And then during the nineteenth century we finally ended up with specialized ice skates, with the skates permanently affixed to a boot of some sort screwed into place, an ice skate that has shoe ices so forth, like you would identify now when you go in like rent ice skates to go ice skating. And the blades were even longer, apparently up to twice the length of the old thirteenth
century skates, enabling even greater balance and maneuverability. And then a whole host of additional innovations have been made and continue to be made, producing skates that are ever more ergonomic, speedy, and effective. Different breaking mechanics were added, blades that ultimately like have a mechanical aspect to them and can shift
and so forth. Saw a Fermente quoted in an article I believe it's the Science Friday, where he basically says that we probably haven't seen as long of a skate as is ideal, like, skates are probably going to keep They're going to keep evolving. They're still evolving, They're becoming more and more efficient, and they may get longer. We have not reached peak ice skate length yet.
Wait, does he have a specific peak length in mind?
Now he's just saying that we're still like fine tuning everything. And I guess the other interesting thing here is that there's not just one purpose for ice skates. There are a lot of highly specialized purposes for ice skates. So you know, we have a whole host of skate based sporting activities and they range from figure skating to ice hockey.
Yeah, I was reading about that too, And an interesting thing there is that apparently different ice temperatures are preferred for the different sports. I think the way I was reading it is that usually they want the temperature a little bit higher for figure skating because figure skaters, I think a softer ice gives them more control over precise movements, whereas with ice hockey, I think they like a slightly colder ice because that allows them to achieve like a higher top.
Speed okay, interesting, Okay, So with hockey it's more about speed, and with figure skating it's maneuverability, which makes it now Fomenty and his co author in the aforementioned paper, they compare the effectiveness of the four main eras of ice skates, and the results illustrate this continual improvement process that we're looking at here. I'm not going to roll through the
entire chart. You can find it in the original paper, but you can see here he breaks things out by speed, stride frequency, stride length, and so forth, and Fermenty points out that with the same metabolic power, skaters today have a speed four times that of our ancestors, and again it's only increasing as we find tune our skate design.
This might not actually be an issue, but I just had the thought. Do skaters on rink ice have higher speeds as well, just because they can feel safe to go at higher speeds, whereas if you're on a natural body of water you might be more I don't know, cautious about like straying into an area of thin ice or something like that.
That's a good point. I mean, I guess the other number of factors that might come into play, right, if you're dealing with like natural ice versus zambonid ice, right.
Yeah, And I know that the zambonid ice, like the rink ice, is laid down one layer at a time to give it special properties, to kind of make it perfect for skating, whereas, of course natural ice on a body of water, I mean, it might be great for skating, but it doesn't have whatever refined quality they're looking for on that rink ice.
Now, I want to come back to ice skating in China because as I was hitting like the core data here, I kept finding various references to Chinese ice skating, and I'd read that ice skating in China might date back to the Song dynasty, so nine sixty to twelve seventy nine. See that is, of course in addition to possibly connected or independent developments in the north of Russia as I
referenced earlier. But certainly I looked into this a little bit more, and you have these ice festivals the Bingshe, which I think means ice amusement festivals that seem to date back to the Song dynasty in China and consisted of various winter sports and performances. Among the many festivities there was a downhill skating event that involved kind of a leather ice skate. I wasn't able to find any images of reproduction of this, but I found some various
modern illustrations of what these might have consisted of. And these these are kind of like curved leather shoes that seem to have been made expressly for sliding across the ice and or snow.
If this is what's depicted in the illustration you put in our outline that kind of curled up at the toe like elf shoes.
Yes, yes, think like leather elf shoes designed for sliding around on ice. It's not skating in the sense that we've been talking about skating, I think from the physics standpoint, But these would have been things that would have been you would have worn for like this downhill skating competition or something that I've seen translated as ice football, in which people were skating around on the ice in these leather shoes throwing some sort of a ball back and forth.
The illustration here that I found is from the Beijing based World of the World of Chinese website, So my understanding is like these are similar but a little bit different. These would have also the examples we're looking at here would have definitely been novelty based skates. These were not about locomotion, These were about amusement. However, in other parts of modern China you do find ancient examples of bone skates.
I was reading that in twenty twenty three, Chinese archaeologists found an example of a bone ice skate in a Bronze Age tomb from roughly three thy five hundred years ago, possibly of the Andronova culture of cattle herders that lived in China's western Shijang Weaker Autonomous Region. These would have been very much akin to what we were talking about, like the bones scrapped to a boot or to a shoe that enabled one to move across naturally frozen bodies
of water. But again, it does seem to come back to bones. It comes back to horse and cow bones strapped to the bottom of your feet, enabling you to at least push yourself across the ice with a big with a pair of poles or sticks.
Well, Rob, you've talked me into it. If I if I take my child ice skating this year, I'm gonna I'm gonna have to get some bone skating to try out see how they do.
You know, I don't think it would be a good idea. I think this would not in the long run, this would be a failure. But I could imagine someone trying to market this. You know, why settle for ice skating when this year when you could do primal ice skating, bone ice skating, and people would be like, yeah, you know, I'm kind of a little over three own axes at the local acts throwing range. I want to try something else that has this kind of like, you know, ancient
vibe to it. Let's strap on some bones and see how it goes. I think you would find it. Would it would? It would be harder. It sounds like every everything I've read about it, it would have been a much harder and clumsier thing to do. We're much better off with modern ice skates, but for.
The metal of it, maybe you use the non metal.
Yes, bone ice skates are very metal. We'll definitely say that.
All right.
Should we wrap up there, Yeah, We're going to go ahead and close out this episode. However, again, definitely tune in later in June when we come back and talk about roller skating on its own again directly connected to the invention of ice skating, but very much its own thing as well. In the meantime, would of course love to hear from everyone out there. Do you have experiences or thoughts related to ice skating? Is there anyone out there who has tried a more archaic version of the
ice skate? If so, definitely right into it because we would love to have your feedback. As always, we'd like to remind you that Stuff to Blow Your Mind is primarily a science and culture podcast, with core episodes on Tuesdays and Thursdays. On Fridays, we set aside most serious concerns to just talk about a weird film on Weird House Cinema. You can find us wherever you get your podcasts and wherever that happens to be and give us some stars and a nice rating that always helps us out.
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